1. Field of the Invention
The invention relates in general to illuminated ceiling structures, and more specifically to decorative drop ceiling structures which include light transmissive lenses.
2. Description of the Prior Art
Certain types of drop ceiling structures include an opaque panel disposed between a source of light and area to be illuminated. The panel includes a plurality of light transmissive lenses disposed in openings formed in the panel. The lenses may be round, square, or any other desired configuration, and the opaque panel may be wood, plastic, or the like, of any one of a plurality of different thickness dimensions. For purposes of appearance, each lens must appear to snugly fit its associated opening, and when viewed from below, the lens must be devoid of any apparent fastening means.
The varying requirements of appearance and structure have been accommodated in the prior art by constructing each lens with a thickness dimension which exceeds the thickness dimension of the opaque panel. The diameter of the lens is also selected to exceed the diameter of the opening. A portion of the outer periphery of the lens is then machined to provide a second diameter portion sized to snugly enter the opening. The shoulder formed on the outer periphery of the lens between the starting diameter and the second diameter rests on the top surface of the panel, to support the lens in the opening.
The usual lens is formed of a polycarbonate resin, with the starting stock being an extruded form. The thicker the lens, the greater the cost. The dimensional tolerance also increases with thickness. The relatively large manufacturing tolerances on the thicker lens cause problems when a plurality of lenses of different dimensions due to this tolerance are machined to provide the second diameter portion of the lens which must snugly fit an opening, and align the lower surface of the lens with the bottom surface of the panel.
Thus, it would be desirable to provide a new and improved illuminated drop ceiling structure which is more adaptable to the varying requirements of appearance and structure, and which is less costly to construct. Of course, the desirable objectives must be achieved without compromising the appearance of the new and improved drop ceiling structure.